GETULIO VARGAS FOUNDATION SÃO PAULO SCHOOL OF ECONOMICS DYNAMIC HEDGING IN MARKOV REGIMES Wagner Oliveira Monteiro Advisor: Rodrigo De Losso da Silveira Bueno, Phd São Paulo 2008 Livros Grátis http://www.livrosgratis.com.br Milhares de livros grátis para download. GETULIO VARGAS FOUNDATION SÃO PAULO SCHOOL OF ECONOMICS DYNAMIC HEDGING IN MARKOV REGIMES Wagner Oliveira Monteiro Advisor: Rodrigo De Losso da Silveira Bueno, Phd Dissertation presented to the São Paulo School of Economics, Getulio Vargas Foundation as one of the requirements for completion of the Masters in Economics São Paulo 2008 Oh friends, no more of these tones! Let us sing more cheerful songs, More joyful. Joy! Joy! Daughter of Elysium! We come …re-touched, Heavenly one, to your shrine. Your magic again binds What custom has divided. All men become brothers, Under the sway of your gentle wing. Whoever has created, An abiding friendship, Whoever has won a loving wife, Yes, whoever calls even one soul theirs, Join in our song of praise; But any that cannot must leave tearfully Away from our circle. All creatures drink of joy At the breasts of nature; All good, all evil, Follow her roses’trail. Kisses gave she us, and wine, A friend, proven unto death; Pleasure was to the worm granted, And the cherub stands before God. Glad, as his suns ‡y Through the Heavens’glorious plan, Run, brothers, your race, Joyful, as a hero to victory. Be embraced, you millions! This kiss for the whole world! Brothers, beyond the star-canopy Must a loving Father dwell. Do you bow down, you millions? Do you sense the Creator, world? Seek Him beyond the star-canopy! Beyond the stars must He dwell. Be embraced, you millions! This kiss for the whole world! Brothers, beyond the star-canopy Must a loving Father dwell. Be embraced, This kiss for the whole world! Joy, beautiful spark of God, Daughter of Elysium, Joy, beautiful spark of God Ludwig van Beethoven, Symphony No. 9, Fourth Movement 1 Acknowledgements It was a very hard task to …nish this dissertation, so I need to thank many people that helped me during this journey. First of all, my parents that always supported me and my brother during our studies. My friends of the Master course. They are many: Ulisses, Luiz Henrique, Fernando Terra, Lucas "Físico", Vitor, Daniel, Juliana, Adriana Dupita, Adriana Sbicca, Renata, Danilo, Bruno, Lucas, Felipe, Marina, Thiago and Felipe Garcia. My friends that have the same advisor: Ricardo Buscarolli and Juliana Inhasz. They could bear the eccentricities1 from our advisor like me. My dear friends outside the Master course: Antonio Noguero (Tonhão) and Robson Santos Sousa (Robinho). All the professors that I had during my studies at School of Economics. My old professor and friend Emerson Fernandes Marçal that accepted to participave in my committes. I thank FAPESP and EESP-FGV for the …nancial support. And I need to thank very much my advisor that helped me a lot during all the time and did not give up on me. 1 strange or unusual, sometimes in an amusing way 2 Abstract This dissertation proposes a bivariate markov switching dynamic conditional correlation model for estimating the optimal hedge ratio between spot and futures contracts. It considers the cointegration between series and allows to capture the leverage e¤ect in return equation. The model is applied using daily data of future and spot prices of Bovespa Index and R$/US$ exchange rate. The results in terms of variance reduction and utility show that the bivariate markov switching model outperforms the strategies based ordinary least squares and error correction models. Key-words: Dynamic Conditional Correlation, Hedge, Markov Regime Switching. JEL Codes: D81, CX53 3 Contents 1 Introduction 6 2 A Bivariate Markov Switching Dynamic Conditional Correlation 2.1 Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Optimal Hedge Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 8 10 12 3 Measuring Hedging Perfomance 3.1 Utility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Variance Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 13 14 4 Data Description 4.1 Ibovespa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Exchange rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 14 17 5 Estimation Results 5.1 Ibovespa . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1.1 Ordinary Least Squares . . . . . . . . . . . . . . . 5.1.2 Error Correction Model . . . . . . . . . . . . . . . . 5.1.3 Markov Switching Dynamic Conditional Correlation 5.1.4 Variance Reduction . . . . . . . . . . . . . . . . . . 5.1.5 Utility . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Exchange Rate . . . . . . . . . . . . . . . . . . . . . . . . 5.2.1 Ordinary Least Squares . . . . . . . . . . . . . . . 5.2.2 Error Correction Model . . . . . . . . . . . . . . . . 5.2.3 Markov Switching Dynamic Correlation Model . . . 5.2.4 Variance Reduction . . . . . . . . . . . . . . . . . . 5.2.5 Utility . . . . . . . . . . . . . . . . . . . . . . . . . 19 19 19 20 21 24 25 26 26 27 28 30 32 . . . . . . . . . . . . Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Comments and Conclusions 32 7 Bibliography 34 4 List of Figures 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Future Ibovespa. From BMF. . Spot Ibovespa. From BMF. . . R$/US$ Future. From: BMF. . R$/US$ Spot. From: BACEN. . Estimated Variance . . . . . . . Correlation . . . . . . . . . . . Filtered Probabilities . . . . . . Optimal Hedge Ratio . . . . . . Expected Optimal Hedge Ratio Variance Estimated . . . . . . . Correlation . . . . . . . . . . . Filtered Probabilities . . . . . . Optimal Hedge Ratio . . . . . . Expected Optimal Hedge Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 15 17 18 22 23 24 24 25 29 30 31 31 31 1 Introduction Agents participants of future markets need to buy a optimal number of futures contracts to minimize the variance of their portfolios returns. The prime articles about this subject were Johnson (1960) and Stein (1961). But only in Ederington (1979) and Figlewski (1984) one can …nd the …rst derivation of the optimal hedge that equals the ratio of covariance between the spot price variation (St ) and the future price variation (Ft ) by the variance of the future price. Since these works, many studies estimated the optimal hedge ratio using di¤erent econometric techniques Di¤erent kinds of estimation methods are used: ordinary least squares [Junkus and Lee (1985)], cointegration [Lien e Luo (1993), Ghosh (1993), Wahab e Lashgari (1993)] and multivariate generalized autoregressive conditional heteroscedasticity models as Kroner and Sultan (1993), Park and Switzer (1995), Gagnon and Lypny (1995, 1997), Brooks, Henry and Persand (2002) and Bystrom (2003). Other possible models are fractional and threshold cointegration as in Lien and Tse (1999), random coe¢ cient as in Bera, Garcia and Roh (1997) and stochastic volatility as in Lien and Wilson (2000). Theses models can not capture all the most important stylized facts found in …nancial series. The ordinary least square does not consider the heterocedasticity and the cointegrated relationship between spot and future prices. The error correction model permits to capture the long run relationship between both series and can have a structure for heteroscedastic errors but this kind of model has not been used to estimate the optimal hedge ratio yet. Multivariate generalized autoregressive conditional heteroscedasticity models as BabaEngle-Kraft-Kroner, here after, BEKK [Engle and Kroner (1995)] and Dynamic Conditional Correlation (DCC) [Engle (2002)] consider the heteroscedastic behaviour of errors but they have mispeci…cation problems because they do not consider the cointegrated relationship. Another problem with theses models is the structurals breaks that can be present in …nancial series. These kind of fact can create an estimation where the conclusion is that there are high persistence in the series but there are not. 6 The aim of this work is to evaluate if a model with a bivariate markov switching regime with two states in the conditional correlation equation of the series can improve the estimation of optimal hedge. For this task we use a bivariate markov switching regime dynamic correlation as in Pelletier (2006) to estimate the optimal hedge for Ibovespa Index and R$/US$ exchange rate. This model was previously used only by Billio and Caporin (2005) in a contagion analysis. In our model we permit the presence of an error correction term and asymmetry in variance equation The di¤erence between the future price and spot price called basis is used as error correction term. According to Fama and French (1987) the basis has a predictive power for the spot returns. There are some articles that had applied markov switching regime models to calculate the optimal hedge ratio. Alizadeh and Nomikos (2004).using an ordinary least squares estimation with markov regime switching. Lee and Yoder (2007) proposed a bivariate markov regime switching BEKK model Lee, Yoder, Mittelhammer and McCluskey (2006) used an autoregressive random coe¢ cient markov switching regime model. Finally, Lee and Yoder (2007) calculate the optimal hedging with a time varying correlation garch regime switching model. The model proposed in my work is similar to the Lee and Yoder (2007) article but the structure considers the cointegrated relationship between data, the leverage e¤ect for univariate variance and permits the unconditional correlation to change in the states. The model is compared with other optimal hedge ratio estimation from ordinary least squares and vector error correction model using the criteria of reduction variance and maximun utility. The results indicate that the model proposed outperforms the other models in-sample. The text is divided as follow: in section two the model is presented and I explain the measured hedging performance, in section three I discuss the data characteristics and afterwards I present the results of estimation. Then I conclude and make some comments. 7 2 A Bivariate Markov Switching Dynamic Conditional Correlation In this section I present the model to estimate the optimal hedge ratio. My intention is to elaborate a model that can capture the stylized facts of the series. Since Mandelbrot (1956) we know that …nancial series usually present facts as clustering, conditional heteroscedastic and assimetry. If a model is not able to capture them, then there will be a mispeci…cation problem. In the case of spot and futures prices the series have a cointegration relationship as shown by Lien and Luo (1993), Kroner and Sultan (1993), Park and Switzer (1995), Lien (1996), Chow (1998) Sarno and Valente (2000), Brooks, Henry and Persand (2002), Yang and Allen (2004), Mili and Abid (2004), Sarno and Valente (2005). In those circustances it is necessary to build a model to embody these characteristics if we want to avoid the mispeci…caation problem The model presented can capture them all. 2.1 Model The model is a bivariate markov switching regime dynamic conditional correlation. First of all, let st and ft be the log of the spot and future prices respectively, St and Ft , and the di¤erence operator, that is where the spot price in t xt 1 . So xt = xt st represents the spot price variation 1 is subtracted from the spot price in t and future variation where the future price in t be ft represent the 1 is subtracted from the future price in t. st = c s + s (ft 1 st 1 ) + "s;t (1) ft = cf + f (ft 1 st 1 ) + "f;t (2) t = "s;t "f;t i:i:d (0; Ht ) (3) Equations 1 and 2 represente the return build on a constant given by cs and cf , an error correction term represented by the di¤erence between future and spot prices in the last 8 period, also know as, the basis of Fama and French (1987) and an error term that has zero average and a variance-covariance matrix given by Ht as in equation 4. (4) Ht = Dt Rt Dt Dt = diag( s;t ; (5) f;t ) 2 s;t =$+ 2 s s;t 1 + 's "2s;t 1 + 2 s "s;t 1 I ("s;t 2 f;t =$+ f 2 f;t 1 + 'f "2f;t 1 + 2 f "f;t 1 I ("f;t 1 1 < 0) (6) < 0) (7) Where I ("t ) is an indicator function that assumes the value 1 for negative values of "t 1 and 0 otherwise. The equations 6 and 7 are the univariate variance of each series, their structures are given by the last variance and the square of last error observed plus the last term used to verify if there is a di¤erence between the variance caused by negative and positive impacts. This part of model follows Glosten, Jagannathan and Runkle (1993) here after GJR. ~ ij Rtij = Q t Qij t = 1 j j j Qj + 1 ~ ij Qij Q t t 0 j t 1 t 1 ~ ij Q t = diag + 1 i j Qt 1 (8) ; where i; j = 1:::2 and q q ij ij q11;t ; q22;t t 1 = Dt 1 t (9) (10) The evolution of Ht is given by a dynamic correlation model. In this case Ht equals Dt Rt Dt as in equation 4 where Dt represents a diagonal matrix with the standard deviation of each series as in equation 5 and Rt is the correlation matrix that depends on an equation of correlation given by Qt as in equation 9. This model has the same structure of Engle’s (2002) DCC model for conditional correlation where the correlations is given by a constant term, the standardized matrix of residuals and the variance-covariance observed in last period. To avoid problems caused by structural breaks as the persistence in the results I use a model that permits the possibility of two di¤erent states in economy for dynamic conditional 9 correlation. This structure is identi…ed by upperscript j and i in equations 8, 9 and 10, where the upperscript j and i refers to the state in t, t 1, respectively. Note that in equation 9 the unconditional correlation has the subscript j indicating that the model permits that its value change in each state. Pr (st = 1) = 2 1 P22;t and Pr (st = 2) = P11;t P22;t 2 1 P11;t P22;t P11;t (11) The ergodic probabilities are given by equations in 11 and indicates the unconditional probabilities of each state. The parameters P11 and P22 are the probabilities of the transition matrix. For details about the asymptotic properties of model DCC see Engle(2002) and Engle and Sheppard (2002) and for the possibility of a markov switching regime dynamic conditional correlation consult Pelletier (2006). 2.2 Estimation The process the estimation of the model is relatively simple. This kind of model is estimate using a two-step Quasi Maximum Likelihood method following Engle (2002) and a modi…ed Hamilton …lter as in Kim(1994). Supose that the full log-lilkelihood can be represented by T T 1X 1X LogL (Y ) = log L (Yt ) = T t=1 T t=1 1 log jHt j + "0t Ht 1 "t 2 (12) but we know from equation 4 that Ht = Dt Rt Dt and is possible to prove that Dt Rt Dt = jDt j jRt j jDt j ;then we conclued that LogL (Y ) = T 1 X 2 log jDt j + log jRt j + "0t Dt 1 Rt 1 Dt 1 "t 2T t=1 10 (13) and replacing "0t Dt 1 for t we have that T 1 X 2 log jDt j + log jRt j + 2T t=1 LogL (Y jD) = t Rt 1 (14) t So it is possible to break the estimate of the model into two stages. In the …rst step I estimate the univariate variance of the each series. With the results from this …rst estimation, it is possible to estimate the correlation structure of the series. In the case of regime switching, Pelletier (2006) demonstrated the possibility of using a modi…ed Hamilton …lter according to Kim (1994), because the value of correlation given by Qt is not observed, as follow: 1. given the …ltered probabilities as inputs, determine the joint probabilities: Pr st = j; st 1 = i j It 1 = Pr (st = j; st 1 = i) Pr st 1 = i j It 1 i; j = 1:::2 (15) 2. evaluate the regime dependent likelihood: Qij t = 1 j j 0 j t 1 t 1 Qj + q ~ ij Q t = diag 1 ~ ij Rtij = Q t LogLt Yt j Dt ; st = j; st 1 = i; I t 1 ij q11;t ; + q i j Qt 1 ij q22;t ~ ij Qij Q t t = (16) i; j = 1:::S (17) 1 (18) 1 log Rtij + 2T 1 Rtij 1 t t (19) 1 (20) 3. evaluate the likelihood of observation t: LogLt Yt j Dt ; I t 1 = S X S X j=1 i=1 LogLt Yt j Dt ; st = j; st Pr st = j; st 1 = i j It 1 = i; I t 1 LogL (Yt ; :::; Y1 ) = LogL (Yt 1 ; :::; Y1 ) + LogLt Yt j Dt ; I t 11 (21) 1 (22) 4. update the joint probabilties: Pr st = j; st 1 = i j It 1 = LogLt (Yt j Dt ; st = j; st 1 = i; I t 1 ) Pr (st = j; st LogLt (Yt j Dt ; I t 1 ) 1 = i j I t 1) (23) 5. compute the …ltered probabilities: Pr st = j j I t = 2 X Pr st = j; st 1 i=1 = i j It j = 1:::2 (24) 6. update the correlation matrix using the following approximation: Qjt = 2 P Pr (st = j; st i=1 1 = i j I t) Qij t Pr (st = j j I t ) (25) 7. iterate 1 to 6 until the end of sample. The bivariate markov switching regime model will be estimated using GAUSS 6.0 software, applyed the Constrained Optimization code2 . To compare the proposed model I estimate the ordinary least squares and vector error correction model too. 2.3 Optimal Hedge Ratio To obtain the variance-covariance matrix for each instant of time, given that I have two di¤erent possible states of economy I use the conditional expectation as in Pelletier (2006) given by equation 26: E [Ht ] = Dt E [Rt ] Dt (26) where Dt is the standard deviations of univariate variance estimation as in equation 5 and Rt is the conditional expectational correlation matrix given by equation 8. To calculate the expected value of Rt is used the expression given by equation 27: 2 I thank Monica Billio and Massimiliano Caporin for the estimation model code. 12 E [Rt ] = R1;t+1 Pr st = 1 j I t + R2;t+1 Pr st = 2 j I t (27) So for each point in time there will be two di¤erent correlations and, consequently, two di¤erents hedge ratios. I will use an optimal hedge ratio calculated from two distincts correlations weighted by their respectives …ltered probabilities given by equations in 11 estimated endogeously in the model. 3 Measuring Hedging Perfomance In this section I present the two di¤erent measurements used in this dissertation to evaluate the optimal hedge ratio. 3.1 Utility This measurement supposes that the agent’s utility function is quadratic as in equation 28. According to the literature, the parameter assumes values between 1 and 4. It rep- resents the risk aversion of the agent. This utility function is used by Kroner and Sultan (1993), Gagnon et al. (1998) and Lafuente Novales (2003) to evaluate di¤erent kinds of hedge strategies. 2 t Et U (rt ) = Et (rp;t ) Where rp;t = st t ft is the return of the agent’s portfolio, the parameter optimal hedge ratio given by each model and V ar ( st t (rp;t ) 2 t (28) is the (rp;t ) is the variance of portfolio given by ft ). The value of Et (rp;t ) is considered zero as in other articles. So the value of the utility will be negative because the values of and 2 t (rp;t ) are positive. The strategy with high utility is the best choice for the agent that are willing to minimize the variance of their portfolio. 13 3.2 Variance Reduction The purpose of the variance reduction is to compare the portfolio variance reduction using the strategy of the estimated model over the strategy where the agent does not buy any future contract. First of all it is calculated the agent’s portfolio variance using 29. V ar (rp;t ) = V ar ( st The parameter t ft ) (29) is the optimal hedge ratio given by each model. Equation 30 shows the variance reduction compared to an unhedge strategy, in other words, a strategy where is zero . 1 V ar (rp;t )h V ar (rp;t )u (30) In 30 the subscript h and u refers to hedge and unhedge, respectively. The higher the value of 30, the better the model is. The model which has the highest value for the statistic outperforms all the other ones. 4 Data Description I used the Bovespa Index spot and future and R$/US$ exchange rate spot and future to estimate the models. The future data sample consists of settlement price from 03=01=2000 to 15=02=2006. To build the series, it is used the most liquid contract near the due date. 4.1 Ibovespa In …gures 1 and 2 we can see the behavior of log level and return for each series. The stylized facts as clustering and variant variance can be veri…ed. And it is possible to see in this sample that the data appear to have a positive trend in log level. As expected, the future and spot series are very similar. So we can expect that conditional correlation be time varying but in a determined level be close to one. 14 10.8 10.4 10.0 9.6 .12 9.2 .08 8.8 .04 .00 -.04 -.08 250 500 750 Return 1000 1250 1500 Log Level Figure 1: Future Ibovespa. From BMF. 10.8 10.4 10.0 9.6 .08 9.2 .04 8.8 .00 -.04 -.08 -.12 250 500 750 Return 1000 1250 1500 Log Level Figure 2: Spot Ibovespa. From BMF. 15 Table 1 has the summary statistics of the series. It is possible to verify that the return of each series has a negative skewness or a negative asymmetry, this fact indicates that using a GJR model for univariate variance is a good choice and that the series has excess kurtosis in …rst di¤erence or return. The value of kurtosis is very low for a …nancial data, near 3. This fact can be explain by a sample characteristic. Table 1 - Summary Log Level Spot Futures Mean 9:742229 9:752695 Median 9:704321 9:718663 Maximum 10:55800 10:55579 Minimum 9:032409 9:035630 Std. Dev. 0:346388 0:344983 Skewness 0:229525 0:220043 Kurtosis 2:190144 2:190886 Statistics Return Spot Futures 0:000579 0:000555 0:000939 0:000984 0:073353 0:091306 0:096342 0:074941 0:018929 0:020011 0:243482 0:029039 4:022739 3:612698 In table 2 I present the result of Unit Root Test3 for future and spot series. All tests say that the serie has a unit root in level and is stationary in the …rst di¤erence. Only by KPSS test we have that the series have a unit root in …rst di¤erence in a level of 1%. This fact can occur because in some point of …gure 2 and 1 it is possible to see high positive and negative values for return that can cause this kind of problem. Table 2 - Unit ADF Future Log Level 0:038 Future Return 38:925 Spot Log Level 0:207 Spot Return 37:923 1% 3:434 5% 2:863 10% 2:567 Root Test PP ERS 0:189 17:832 39:009 0:059 0:302 21:040 37:929 0:082 3:434 1:99 2:863 3:26 2:567 4:48 KPSS 2:772 0:390 2:778 0:407 0:739 0:463 0:347 In table 3 I present the Johansen Cointegration test applied with no trend and an irrestrit constant4 . The result of the test is that the series are cointegrated in level. This indicate 3 I applied the Augmented Dickey-Fuller (ADF), Phillips-Perron (PP), Kwiatkowski, et. al. (KPSS), Elliot, Richardson and Stock (ERS) Point Optimal test. 4 But for all possibles combinations I found out at least one cointegration relations 16 that the model needs to consider this relationship when modelling the joint behavior of the series. Table 3 - Johansen Cointegration Test No CE Trace Statistic Critical Value Max-Eingen Statistic Critical Value None 140:157 15:494 140:142 14:264 At most one 0:015 3:841 0:015 3:841 4.2 Exchange rate In …gures 3 and 4 I show the behavior of the log level and return of exchange rate data. Again it is possible to see that the stylized facts are present in these series. But di¤erent from index data this one does not have a trend. So, it is interesting to use our model in these two di¤erent data. 8.4 8.2 8.0 7.8 .08 7.6 .04 7.4 .00 -.04 -.08 -.12 250 500 750 Log Level 1000 1250 1500 Return Figure 3: R$/US$ Future. From: BMF. In Table 4 I present the summary statistics of the spot and future exchange rate in log level and in return. Again it is possible to say that the series have negative skewness but the excess of kurtosis in …rst di¤erence is much higher for currency data compared with index data. So exchange rate series present the common …nancial series stylized facts. 17 8.4 8.2 8.0 7.8 .05 7.6 7.4 .00 -.05 -.10 250 500 750 Log Level 1000 1250 1500 Return Figure 4: R$/US$ Spot. From: BACEN. Mean Median Maximum Minimum Std. Dev. Skewness Kurtosis Table 4 - Summary Statistics Log Level Return Spot Futures Spot Futures 7:837422 7:841825 9:46e 05 8:25e 05 7:849246 7:856752 0:000180 0:000346 8:282685 8:284450 0:047583 0:061572 7:451822 7:452724 0:093604 0:105023 0:201346 0:200539 0:009513 0:010949 0:176943 0:208389 0:509710 0:120257 2:282702 2:257729 12:40289 11:99867 In Table 5 it is presented the result of Unit Root Test for future and spot exchange rate in log level and …rst di¤erence. All tests say that the series has a unit root in level and is stationary in the …rst di¤erence but this is not true for KPSS test in a level of 1%. Again this fact can occur because in some points of …gures 2 and 1 it is possible to see high positive and negative values for return. 18 Table 5 - Unit Root Test ADF PP ERS Future Log Level 1:4241 1:397 36:034 Future Return 41:689 41:677 0:057 Spot Log Level 1:408 1:449 47:095 Spot Return 28:651 32:243 0:074 1% 3:434 3:434 1:99 5% 2:863 2:863 3:26 10% 2:567 2:567 4:48 KPSS 1:995 0:562 1:977 0:598 0:739 0:463 0:347 In Table 6 I present the Johansen Cointegration test applied with a costant and without trend 5 . The result of this test is that the series are cointegrated in level. So it is possible to say again that the model needs to consider this relationship when modelling the joint behavior of series. Table 6 - Johansen Cointegration Test No CE Trace Statistic Critical Value Max-Eingen Statistic Critical Value None 300:143 15:494 298:078 14:264 At most one 2:065 3:841 2:065 3:841 5 Estimation Results In this section I present the results from the estimated models: ordinary least square, vector error correction model and bivariate markov switching regime model for each data series. 5.1 5.1.1 Ibovespa Ordinary Least Squares In equation 31 I show the result of the Ordinary Least Squares model. It is possible to note that all estimated parameters are signi…cant at 5%. Using this model I conclude that the optimal hedge is 0:88. This will be the value used to evaluate the optimal hedge ratio strategy calculated from ordinary least squares model. For this model the R2 statistic is 0:89. 5 But for all possibles combinations I found out at least one cointegration relations 19 st = 0:00008 + 0:885 (0:0001) (31) ft (0:008) Only for the good of science or perhaps curiosity I estimate an ordinary least squares model with an extra variable: the basis. The result is shown in equation 32 In this case I can infer that the constant parameter and the new parameter included have statistical signi…cance. So I veri…ed that the value of the basis in t 1 has statistical signi…cance to explain the exchange rate spot return in t.The R2 statistic is of 0:90. st = 0:002 + 0:90 (0:0002) ft (0:007) 0:206 (0:015) (ft 1 (32) st 1 ) I use the optimal hedge ratio from 31 because in 32 the parameter of future variable return is not any more equal the ratio between covariance of spot and future return and the variance of future return. 5.1.2 Error Correction Model The Error Correction Model results can be observed in equations 33, 34 and 35. The adjustment parameter is not signi…cant in the equation of spot returns given by equation 33 but it is in the equation of future returns given by equation 34, so I can infer that it is the future price that adjusts the long-run relationship. The spot prices appear not to have an autoregressive component and the value of future price in t 1 can not help explaining the value of spot price in t given that these two parameters are not signi…cant. For future prices it happened the opposite, the last value of spot prices and the autorregressive compenent are signi…cant to explain the value of future price in t. This fact indicates that future prices adjust itself after a shock to keep the long-run relationship. st = 0:0005 + 0:046 (0:0004) (0:083) st 1 0:008 (0:078) 20 ft 1 + 0:046 (0:055) zt 1 (33) ft = 0:0005 + 0:227 (0:00051) st (0:088) where zt 1 = ft 1 0:188 1 ft (0:083) 0:995 st 1 (0:002) 1 0:156 zt (0:058) (34) 1 (35) 0:058 The parameter value in the cointegrated vector given by equation 35 estimated is significant at 5% and is nearly 1. A probable indication that the basis can be used as an error correction term. To calculate the optimal hedge ratio for this model it is necessary to calculate the ratio between the covariance of residuals from equations of spot and future returns given by equations 33 and 34 and the variance of residuals from equation of future return given by equation 34. The value that I have found out was 1:0166. 5.1.3 Markov Switching Dynamic Conditional Correlation Model In equations 36 and 37 I can verify the results for equation return of each index series. The parameter that represents the error correction term is signi…cant only in future return equation, as seen in the results of error correction model. st = 0:0001 + 0:040 (0:046) (0:046) (ft 1 st 1 ) (36) ft = 0:002 0:166 (ft 1 st 1 ) (37) (0:0006) (0:046) The results of the variance equation for each serie are in equations 38 and 39. We can note that the model captures a leverage e¤ect, or in other words, the model capture of di¤erent ways negative impacts ("bad news") and positive impacts in variance equation as in the literature. 2 s;t = 0:00001 + 0:928 (0:000003) (0:017) 2 s;t 1 0:008 "2s;t (0:01) 21 1 + 0:087 I ("s;t 1 ) (0:016) "2s;t 1 (38) 2 f;t 2 f;t 1 = 0:000009 + 0:943 (0:000002) (0:013) 0:011 "2f;t (0:009) 1 + 0:085 "2f;t I ("f;t 1 ) (0:016) (39) 1 In …gure 5, I plot the estimate variance for both sample series. .0016 .0016 .0014 .0012 .0012 .0010 .0008 .0008 .0006 .0004 .0004 .0002 .0000 .0000 250 500 750 1000 1250 1500 250 500 Future 750 1000 1250 1500 Spot Figure 5: Estimated Variance In the second stage, I estimate the conditional correlation between series using the residuals from the univariate variance estimations. The results are shown in equations 40 and 41. According to the estimates, there are two di¤erent states for series correlation. In state one, the unconditional correlation is equal 0:980 and in state two, the value is 0:605. I can infer that both estimated parameters are signi…cant at 5%. So in state one there is a high positive correlation between series and the state two has a low correlation between series. The parameter estimated are not signi…cant and in state one the vale of parameter Q1t = 1 Q2t = 1 0 (0:021) 0:014 (0:051) 0:019 (0:063) 0:331 (0:468) 0:980 + 0 (0:021) (0:001) 0:605 + (0:051) 0 (0:034) 0 t 1 t 1 + 0:019 0 t 1 t 1 + 0:331 (0:063) (0:468) Q1t Q2t is zero. (40) 1 1 (41) In …gure 6 is shown the behavior of estimated correlation. I can infer that in state one there is a high correlation and state two the correlation is lower than state one again. In 22 state one the range of correlation is equal 0:007 but in a high level correlation and in state two the correlation range is high but in a lower level compared with state one. .981 .80 .980 .76 .979 .72 .978 .977 .68 .976 .64 .975 .60 .974 .973 .56 250 500 750 1000 1250 1500 250 State 1 500 750 1000 1250 1500 State 2 Figure 6: Correlation In Table 7 are the transitions probabilities of the model. Using this information we can conclude that state one has a duration of of 1 1 0:4879 1 1 0:9498 = 19: 92 days and state two has a duration = 1: 952 7 days. The ergodic probabilities are given by for state one and 1 0:9498 2 0:9498 0:4879 1 0:4879 2 0:9498 0:4879 = 0:910 72 = 0:089 28 for state two. So we can conclude that for this sample, the probability of conditional correlation between series is bigger for state one than state two. Table 7 - Probabilities Transition State One State Two State One 0:9498 0:050 2 State Two 0:512 1 0:4879 In …gure 7 I show the …ltered probabilities of each state. They indicate that in each state the probability of been in state one is bigger than state two for each t. I plote in …gure 8 the optimal hedge ratio estimate in each state. Both series are very similar. In the state one the correlation between spot and future Ibovespa index is close to one so the optimal hedge ratio is close to one too for each t: In the state two the value of optimal hedge ratio is less than that of state one because the conditional correlation between the series presents this behavior too. Another observation is that both graphs are similar 23 1.0 1.0 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0.0 0.0 250 500 750 1000 1250 1500 250 500 State 1 750 1000 1250 1500 1000 1250 1500 State 2 Figure 7: Filtered Probabilities 1.1 1.1 1.0 1.0 0.9 0.9 0.8 0.8 0.7 0.7 0.6 0.6 0.5 0.5 250 500 750 1000 1250 1500 250 500 State 1 750 State 2 Figure 8: Optimal Hedge Ratio but in di¤erents levels. In …gure 9 are the expected optimal hedge ratio calculated using the hedge ratio in each state and their respectives …ltered probabilities. The serie ‡oats between 0:9 and 0:8. In some points there is a trend to achieve values close of 0:6. 5.1.4 Variance Reduction In Table 8 are the results of model’s evaluation using the variance reduction criterion. Second this judge the best strategy in-the-sample is given by switching regime model reducing the variance in 89:86% followed by ordinary least squares model that can reduce the variance 24 1.1 1.0 0.9 0.8 0.7 0.6 0.5 250 500 750 1000 1250 1500 Figure 9: Expected Optimal Hedge Ratio in 89:44%, the values are very close. Table 8 -Variance Reduction Variance Reduction Unhedge 0:0003510351797 Naive 0:0000423391708 87:94% OLS 0:0000370814818 89:44% ECM 0:0000435916178 87:58% MSDCC 0:0000355961241 89:86% The values for variance reduction is very high, almost 90% so I can conclude that some kind of strategy buying future contracts of Ibovespa index can reduced signi…cantly the variance of agent’s portfolio. 5.1.5 Utility In Table 9 are presented the values of utility obtained by equation 28 using the results of each model or strategy. For all value of coe¢ cient risk aversion the switching regime model is the better choice compared with ordinary least squares and vector error correction models. The curios fact is that the naive strategy is a better choice than vector error correction model. 25 Risk Aversion Unhedge Naive OLS ECM MSDCC 5.2 5.2.1 Table 9 - Measure Utility Utility 1 2 3 0:000351 0:000702 0:001053 0:000042 0:000085 0:000127 0:000037 0:000074 0:000111 0:000044 0:000087 0:000131 0:000036 0:000071 0:000107 4 0:001404 0:000169 0:000148 0:000174 0:000142 Exchange Rate Ordinary Least Squares In equation 42 I can evaluate the result of the ordinary least squares model. It is possible to note that only the parameter of future return is signi…cants at 5%. Using this model I conclude that the optimal hedge is 0:535 for exchange rate, a less value when compared with index optimal hedge ratio from ordinary least squares. This will be the value used to evaluate the optimal hedge ratio calculated from ordinary least squares model. For this model we have a R2 statistic of 0:38. The values of the optimal hedge ratio parameter and R2 statistic is less than compared with the values for index results. st = 0:00005 + 0:535 (0:0001) (0:017) (42) ft As before I estimate an ordinary least squares model with a one more variable in the model: the basis. The result is presented in equation 43 In this case the constant parameter and the new parameter include have statistician signi…cant. So it is possible to say that the basis in t 1 has statistician signi…cant to explain the return of spot exchange rate in t. The R2 statistic is of 0:63. st = 0:002 + 0:583 (0:0001) (0:013) ft + 0:634 (0:019) (ft 1 st 1 ) (43) Note how the value of R2 increased with an addiotinal explicative variable when compared with the same situation in index results. I use the optimal hedge ratio from 42 because in 26 43 the parameter of future return explicative variable in equation 43 is not any more equal the ratio between covariance of spot and future return and the variance of future return as in equation 42. 5.2.2 Error Correction Model For Error Correction Model the results to exchange rate can be observed in equations 44, 45 and 46. It can be noted that the parameter of adjustment is signi…cant in both equations and assumes a positive value to spot equation and a negative value to future equation. So I can infer that both prices adjust the long-run relationship and that spot exchange rate needs to increase and future exchange rate needs to decrease to do it. The spot prices appear not to have an autoregressive component and the value of return future price in t 1 can help predicting the value of spot price in t. For future prices, the last value of spot prices and an autoregressive component are signi…cant to explain the value of future price in t. st = 0:00006 (0:0002) 0:001 (0:031) ft = 0:0008 + 0:117 (0:00028) (0:040) where zt 1 = ft st 1 st 1 1 +0:222 (0:078) 0:093 (0:042) 0:996 st (0:001) 1 ft 1 ft 1 + 0:369 (0:037) zt 0:094 zt (0:048) 0:033 1 1 (44) (45) (46) A last comment is about the cointegration vector. The parameter value estimated is signi…cant at 5% and is nearly 1. A probable indication that the basis can be used as a proxy of an error correction term. To calculate the optimal hedge ratio for this model is necessary to calculate the ratio between the covariance of residuals from equations 44 and 45 and the variance of residuals from equation 45. The value found out were 1:0069. A value higher than that one predicted by the ordinary least squares model. 27 5.2.3 Markov Switching Dynamic Correlation Model In equations 47 and 48 it is possible to verify the results for equation return of future and spot exchange rate. The parameter value of basis is signi…cant in both equations as in error correction model. It is observed that the signs of the parameter’s error correction term is the same that those found out in equations 44 and 45, indicating that to repair the long-run relationship it is necessary that spot exchange rate increase and that future exchange rate decrease. So both data need adjustment to repair the long-run relationship. st = 0:002 + 0:521 (0:0001) ft = 0:0008 (0:0002) (0:024) 0:172 (0:035) (ft (ft 1 1 st 1 ) (47) st 1 ) (48) The results of the univariate variance to spot and future exchange rate are in equations 49 and 50, respectively. Note that the model captures a leverage e¤ect, or in other words, the model captures of di¤erent ways negative impacts and positive impacts as in literature for both variance equations. Anotther interesting fact to note is that sign of the leverage e¤ect parameter is negative, the opposite of index results indicating that negative impacts reduce the variance. 2 s;t 2 f;t = 0:00001 + 0:808 (0:000003) (0:018) = 0:00001 + 0:877 (0:000003) (0:012) 2 s;t 1 + 0:245 "2s;t 1 2 f;t 1 + 0:137 "2f;t 1 (0:026) (0:015) 0:132 I ("s;t 1 ) (0:025) 0:044 (0:015) I ("f;t 1 ) "2s;t "2f;t 1 1 (49) (50) In …gure 10 I plot the variances estimatives of both series. According to them I can infer that the variance of spot exchange rate and the variance of future exchange rate are very similar and that they are clearly variant in time. In the second stage, I estimate the conditional correlation between series using the residuals from the univariate models. The results are in equations 51 and 52. According to the 28 .0020 .0020 .0016 .0016 .0012 .0012 .0008 .0008 .0004 .0004 .0000 .0000 250 500 750 1000 1250 1500 250 500 Future 750 1000 1250 1500 Spot Figure 10: Variance Estimated estimates there are two di¤erents states for correlation between spot and future exchange rate. In state one the unconditional correlation is equal 0:899 and in state two this value is 0:560. The estimatives parameters and estimated are not signi…cant and in state two, given by equation 52, the value of parameter Q1t = 1 Q2t = 1 0:005 (0:029) 0 (0:034) 0:681 (0:111) 0:597 (0:214) is zero. 0:899 +0:005 (0:029) (0:039) 0:560 + (0:075) 0 (0:034) 0 t 1 t 1 + 0:681 0 t 1 t 1 + 0:597 (0:111) (0:214) Q1t Q2t 1 1 (51) (52) In …gure 11 I plote the behavior of estimated correlation between series. For state one the estimated correlation between spot and future exchange rate ‡oats around a level of 0:8 and for state two the correlation ‡oats around a level of 0:6, as expected, a positive and high value, very close to one. This can indicate that both series are almost always very close and in some moments their keep a high correlation but in a lower level. In table 10 are the transitions probabilities of the model. Using this information I can conclude that in average the state one has a duration of has a duration of 1 1 0:804 1 1 0:8420 = 6: 329 1 days and state two = 5: 102 days. The ergodic probabilities are given by 0:553 67 for state one and 1 0:842 2 0:8420 0:804 1 0:804 2 0:8420 0:804 = = 0:446 33 for state two. So we can conclude that 29 1.0 1.0 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0.0 0.0 250 500 750 1000 1250 1500 250 State 1 500 750 1000 1250 1500 State 2 Figure 11: Correlation for this sample the probability that conditional correlation between series is bigger for state one than state two but not much and it is more probable that the spot and future exchange rate have a higher correlation close to 0:8 as in …gure 11. Table 10 - Transition Probabilities State One State Two State One 0:8420 0:158 0:804 State Two 0:196 In …gure 7 it is observed the …ltered probabilities for each state. Their indicate that the probability of been in state one is almost the same of been in state two for each t in average, this behaviour is expected because the ergodic probabilities obtained by model. I plote the optimal hedge ratio estimated in each state in …gure 13. Both series are very similar. and they ‡oat almost around the same level, di¤erently of the optimal hedge ratios results obtained by Ibovespa Index and reported in …gure 8. In …gure 14 are ploted the expected optimal hedge ratio for each t. I can infer that the behavior of graph is very similar compared to …gure 13. 5.2.4 Variance Reduction Table 11 present the results of model’s evaluation using the variance reduction criterion to exchange rate. I can infer that using some kind of strategy, then the agents can reduce the 30 1.0 1.0 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0.0 0.0 250 500 750 1000 1250 1500 250 500 State 1 750 1000 1250 1500 1000 1250 1500 State 2 Figure 12: Filtered Probabilities 1.4 1.4 1.2 1.2 1.0 1.0 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0.0 0.0 250 500 750 1000 1250 1500 250 500 State 1 750 State 2 Figure 13: Optimal Hedge Ratio 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 250 500 750 1000 1250 1500 Figure 14: Expected Optimal Hedge Ratio 31 variance of his portfolio as the results obtained by Ibovespa index and that the best strategy in-the-sample is given by the switching regime model. A curios fact is that the variance reduction obtained by vector error correction model (8:82%) is very small when compared with variance reduction obtained by ordinary least squares (38:15%) and switching regime model (39:73%) and a naive strategy is a better choice to an optimal hedge ratio than vector error correction term. Table 11 - Variance Reduction Variance Variance Unhedge 0:0000904814249 Naive 0:0000817149847 9:69% OLS 0:0000559637992 38:15% VECM 0:0000824974200 8:82% MSDCC 0:0000545306447 39:73% 5.2.5 Utility In table 12 are present the values of utility. For all values of coe¢ cient risk aversion the switching regime model is the better choice for exchange rate data. The same result obtained by index data. The vector error correction model is a worse choice when compared with a naive strategy, the same result found out in table 9 for Ibovespa Index. Table 12 Utility Risk Aversion Unhedge Naive OLS VECM MSDCC 6 1 0:000090 0:000082 0:000056 0:000082 0:000055 2 0:000181 0:000163 0:000112 0:000165 0:000109 3 0:000271 0:000245 0:000168 0:000247 0:000164 4 0:000362 0:000327 0:000224 0:000330 0:000218 Comments and Conclusions The results achieved in this dissertation need some further explanation and comments. For both series some estimated parameters of the conditional correlation equation are zero or not signi…cant but the unconditional correlation and the transition probabilities are 32 signi…cant. So this econometric model says that the probabilities and the unconditional correlation are more important to determine the correlation in each point of time and that there is a switching regime in the correlation data. The fact that the equation parameters are not signi…cant can be a little strange but it is supported by the high correlation behavior that can be assumed from the log level graphs. The future and spot prices are very narrowly related, so the correlation or covariance between them is high during all the time and sometimes it can change to a lower level. Then for the estimated structure, unconditional correlation and probabilities are important. The correlation is always ‡uctuating around these two levels of the estimated unconditional correlation. The …ltered probabilities indicate that the correlation between the series does not stay in each state for a long time, as we can see in the pictures of the …ltered probabilities. These results, perhaps, can not have an economic interpretation but Lee, Yoder, Mittelhammer and McCluskey (2006) found very similar …ltered probabilities to those I found in my work and Lee and Yoder (2007) presented, similarly to my work, not only the …ltered probabilities but also some parameter that are not signi…cant and some equal zero. Concluding, in this work I estimated the optimal hedge ratio using a bivariate markov switching regime dynamic conditional correlation that incorporate a leverage e¤ect in univariate variance and an error correction term. The model was applied in two di¤erent data series. The results from the variance reduction and utility indicate that this model is a better choice when compared to ordinary least squares and vector error correction model. 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